Device for introducing motion into sealed instruments



April 15, 1947. H T, JR 2,419,074

' DEVICE FOR INTRODUCING MOTION INTO SEALED INSTRUMENTS Filed July 21, 1945 ATTORNEY Patents Apr. 15, 1947 ngn STATES PATENT OFFICE DEVICE FOR INTRODUCING MOTION INTO SEALED INSTRUMENTS Frederick D. Herbert, Jr., Upper Montclair, N. 3., assignor, by mesne assignments, to Kearfott Company, Inc., New York, N. Y., a corporation of New York Application July 21, 1945, Serial No. 606,418

2 Claims.

1 This invention relates to motion transmitting units which are adapted for the introduction of movement from an external source into a sealed the axis, in other Words, upon the inclination of the lever to the axis with a given spacing of the driving and driven members.

In order to preserve the seal, it is well known that devices of this sort may employ a flexible bellows having one end free for movement and hermetically sealed to the lever, and its other end fixed and secured so as eifectively to seal the interior of the mechanism casing about the input member.

Embodiments of the present invention are particularly designed and adapted for the purpose of introducing slight adjustments into a sealed mechanism, such as is commonly effected by the turning of a screw head. An example of such adjustment is what ,are known as zero resets or adjustments, where a slight adjustment of spring tension may be required occasionally to cause a hand to return accurately to zero from a positive reading.

Since such transmission units may be of mini- -ature size with a head not much larger than a screw head and permissively provided with a 'screw slot for engagement by a screw driver, it

is a purpose of this invention to provide a combined transmitting and sealing construction of the type described which will be particularly adapted for incorporation in such small units.

Other general objects of the invention are simplicity of design, reliability in operation, ease of manipulation and durability in construction. Still other objects and advantages of the invention will appear from the following description.

One of the features of the invention which particularly adapts it for small size units is the elimination of the usual ball and socket type of pivot for the oblique lever. Instead the lever has a virtual-rather than an actual or physical pivot. Specifically the device includes a cap or small, cup shape housing simulating a knob, the open end of which rotatively bears on a plate having an axial hole through which the lever end protrudes. Inside the cap or housing are the bellows and the lever operatively connected in such manner as to dispense with a physical universal socket.

More particularly, the lever is in two telescopic parts, one part, which is the outer part, being carried by the head of the bellows and including 1 the operating end, and the other part being carried by and fixed to the head of the cap or housing and inclined to the axis and intersecting it. The point of intersection and the angle of the lever to the axis of the housing determine the locus of the pivot and the diameter of the are described by the protruding end of the lever. Preferably the part of the lever which is carried by the cap head is eccentrically attached thereto, and the inclination is such as to bring the intersection well within the bellows and relatively. close to the head end thereof, so asto minimize the lateral component of movement of. the free end of the bellows.

The illustrated embodiment of the invention will now be described, after which the invention will be pointed out in claims.

Fig. 1 is a perspective of a unit embodying the invention.

Fig.- 2 is a sectional elevation of the same on enlarged scale and showing a portion of a casing and a part to be driven in operative relation thereto.

Fig. 3 is a sectional plan'on' the plane indicated by the line 3-3 in Fig. 2.

Referring to the drawing more in detail, the invention is shown as applied to a device for adjusting a set screw in which is rotative in a fixed support Hand is provided with a head l2 having a screw driver slot i3. The set screw ill, however, is representative of any rotary member which is to be actuated by external means. The set screw 10 is mounted within a closed chamber having a sealed external casing i4 only a portion of which is shown.

The casing I4 is provided with an opening registering with the set screw Ill in which. an annular plate i5 is sealed. The plate I5 is provided with an external flange l6 having a shoulder ll which seats against the casing I4. The plate l5 may be sealed in place by suitable means such as a ring of solder l8.

The annular plate I5 is provided with a central opening 20 registering with the set screw ID. A flexible bellows 2| of suitable metal surrounds the opening 20 and one end of the bellows is flanged over the plate I5 to form a sealing flange 22 which is sealed to the plate 65 by suitable means, shown at a ring oi solder 28.

The other end of the bellows 29 is sealed to a, head 80 b means shown as a ring of solder 3!. The head 38 is formed with a hollow, inwardly projecting cylindrical member 32, having a closed end 33 terminating in a pin 34 which protrudes through the opening 28 and is positioned and shaped to enter the slot i3 01' the screw ID.

A cap it is provided with an annular flange 4| which is journalled in the flange I 8 01' the plate lb and is secured in position by a split ring 42 seated in an annular groove in the flange I 6. The can db is formed with a top 43 having a screw driver slot ti therein and, may have a knurled external surface 65. A pin 46 is formed integrally. with or is attached to the inside of the top 43 oi the cap til. The pin 49 is inclined to the axis of the cap it and in the embodiment shown is attached eccentrically to the top 43 and intersects the axis of the cap at the point Al. The pin 48 his into and turns in the cylindrical member I: and at its end engages a ball it which rests against the end it of the cylindrical member and forms a thrust bearing to so position the bellows 29 that suitable clearance is provided between the head 8% and the top 33 of the cap 40.

In assembling the device the bellows carryingthe head 3b is first attached to the plate 55. The

can it is then positioned with the pin 68 suitably inserted in the member 32 and is secured by the split ring 52. The unit thus formed may be inserted in the casing it and secured by the ring of solder i8. 7

In operation, turning the can It causes the pin 68 to swing about the point." inthe same manstricted to the particular 3 4 30 of the bellows the rocking movement of the head 30 and consequent deflection or the bellows tive movement about its axis, a flexible bellows in the cap'having one end attached to the plate about the hole and sealed thereto, a head attached to and sealing the other end of the bellows and having an axial extension on its inner face protruding through the hole in the plate and having an axial bore for a portion of its length ner as though a fixed bearing were provided at that point. The bellows 2i and head 30 rock with the movement of the pin 46 but do not rotate as the pin it is mounted to rotate freely within the member 32. The pin 8% forms in efi'ect an extension or the pin 43 but is located within the bellows and rocks or swings about" the point 6! without rotating about its own axis. The end or the pin it thus describes an arc corresponding to the arc of movement of the external can do and, being eccentrically constrained in the not. it, causes a corresponding adjustment or the set screw it. The device accordingly transmits rotary motion through the medium or a nonro-r tating shaft which is sealed within a flexible belilows. R

It is to be noted that the point 4'! at which the pin it intersects the axis of the cap may be shifted along the axis of the cap it by varying the inclination of the pin 46 d its point of at tachment to the cover 63. In the embodiment shown the point it? lies at about the mid-point oi the bellows 2 i As the point approaches the head at its attached end, and an angularly pin attached to the headoi the cap and entered into said bore.

2. A device for transmitting rotary motion to a rotary member within a sealed casing from an external member, comprising a plate having a hole therein and adapted to be hermetically attached to a'casing. a cap covering said hole and bearing with its open end on the plate for rotative movement about its axis. a flexible bellows in the up having one end attached to the plate about the hole and sealed thereto, a head attached to and sealing the other end or the bellows and having an axial extension on its inner face protruding through the hole in the plate and having anaxial bore for a portion of its-lentth at its attached end, a pin eccentrically attached to the head of the cap and entered into said bore and extending at an angle to and intersecting the axisof the bellows. and a ball in the bottom of the-bore engaged by'the end of said pin and act- Number I ing as a thrust bearing to determine the spacing of the bellows head from the cap head.

' FREDERICK D. HERBERT, Jr.

REFERENCES CITED UNITED STATES mrrm'rs Name Date 1,514,968 Hull Nov. 11, 1924 FOREIGN PATENTS Number Country Date 98,132 Swiss 1923 

